Dr Julian Lewis: I rise to request urgent clarification of the radical reductions in conventional military forces provisionally proposed by the National Security Capability Review, together with an explanation of the reasons for undertaking the review and the financial constraints under which it is being conducted.

The Secretary of State for Defence (Gavin Williamson): In the 2015 Strategic Defence and Security Review, the Government identified four principal threats facing the UK and our allies in the coming decade: terrorism, extremism and instability; state-based threats and intensifying wider state competition; technology, especially cyber-threats; and the erosion of the rules-based international order.

As the Prime Minister made clear in her speech to the Lord Mayor’s banquet late last year, these threats have diversified and grown in intensity. Russian hostility to the West is increasing – whether in weaponising information, attempting to undermine the democratic process or increased submarine activity in the North Atlantic. Regional instability in the Middle East exacerbates the threat from Daesh and Islamic – Islamist terrorism, which has diversified and dispersed. Iran’s well known proxy military presence in Iraq, Syria and elsewhere poses a clear threat to UK interests in the region and to our allies.

Like other Members, I have seen much of the work that our Armed Forces continue to do in dealing with these threats. It is because of these intensifying global security contexts that the Government initiated the national security capability review in July. Its purpose is to ensure that our investment in national security capabilities is joined up, effective and efficient. As I said in Oral Questions, since I became Defence Secretary I have asked the Department to develop robust options to ensure that Defence can match the future threats and challenges facing the nation. Shortly, when the National Security Capability Review finishes, the Prime Minister, with National Security Council colleagues, will decide how to take forward its conclusions. I would not wish to pre-empt that decision.

Although the detail must wait until after the NSCR concludes, I can assure the House that as long as I am Defence Secretary we will develop and sustain the capabilities necessary to maintain continuous at-sea nuclear deterrence, a carrier force that can strike anywhere around the globe and the Armed Forces necessary to protect the north Atlantic and Europe; and we will continue to work with our NATO allies. The Prime Minister, the Chancellor and I will be doing all we can to ensure that we have a sustainable budget, so that we can deliver the right capabilities for our Armed Forces.

Dr Lewis: I thank the current Defence Secretary – [Laughter.] That is not meant to be funny. I thank him for confirming what the previous Defence Secretary told the Defence Committee, namely that the capability review resulted from intensified threats to the United Kingdom. If the threats are intensifying, why has the review provisionally proposed radical reductions in our conventional armed forces, and why is it required to be ​fiscally neutral, as the National Security Adviser recently told the Joint Committee on the National Security Strategy? Who has imposed that financial restriction? The Ministry of Defence? Unlikely. The Treasury? Almost certainly.

If new threats have intensified, is not more money needed, unless of course previous conventional threats have seriously diminished? If previous conventional threats have diminished, why did the National Security Adviser claim to the Defence Committee in a letter:

“Because the main decisions on Defence were taken during the 2015 SDSR, this review is not defence-focused”?

If this review is not defence-focused, and if the 2015 plan therefore still applies, why should thousands of soldiers, sailors and airmen be lost, elite units merged or aircraft, frigates and vital amphibious vessels scrapped, long before their out-of-service dates?

Finally, is it not obvious that we are bound to face such unacceptable choices as long as we continue to spend barely 2% of GDP on Defence? Even after the end of the Cold War and the taking of the 'peace dividend' cuts, we were spending fully 3% in the mid-1990s. Defence is our national insurance policy, and it is time for the Treasury to pay the premiums.

Gavin Williamson: I thank the current Chairman of the Defence Committee – I think we are only ever current – for raising those points. In the NSCR, we are looking at the threats that the country faces, and everything that was done in 2015 is relevant today. As I pointed out, the Prime Minister herself has highlighted the fact that the threats are increasing, and we are having very active discussions right across Government about how best we can deal with those threats. There is an awful lot of speculation and rumour in the press, but that is what we expect of the press.

As I mentioned earlier, we need to ensure that we have the right capability, whether that is a continuous at-sea nuclear deterrent, our Special Forces, or an Army, Navy and Air Force that have the right equipment and capability to strike in any part of the globe. That is what we have to deliver. I am afraid that I cannot be drawn on the details at the moment, but I will be sure to update the House regularly, as the National Security Capability Review develops, on the conclusions of the review and how we can best deal with them.